Rock-drill



2 Sheets-Sheet 1.

N A Mm D.. AM HD Cm .0 ,WR T n. d 0 M o m Patented July Z, 1895.

ATTORNEY I (No Model.) `2 Sheets-Sheet 2.

T. W. CHAPMAN. ROCK DRILL.

No. 542,010. Patented JulyZ, 1895.

-llllll IN VEN T OR A7.- W C/vmz l M ATTORNEY NrTED STATES THERON W. CHAPMAN, OF LAKEIVOOI'), COLORADO.

ROCK-DRILL.

SPECIFICATION forming part of Letters Patent No. 542,010, dated July 2, 1895. Application led August 27, 1894- Serial No. 52l,362. (No modela To a/ZZ whom may concern:

Be it known that I, THERON W.-CHAPMAN, a citizen of the United States of Americanesiding at Lakewood, in the county of Jefferson and State of Colorado, have invented certain new and useful Improvements in Rock- Drills; and I do declare the following to be av full, clear, and exact description of theinvention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had tothe accompanying drawings, and to the figures of reference marked thereon, which form a part of this specification.

My invention relates to improvements in Arock-drills, and consists of the features, ar-

rangements, and combinations hereinafter described and claimed, all of which will be fully understood by reference to the accompanying drawings, in which is illustrated an embodiment thereof.

In the drawings, Figure 1 is a side elevation of the drill, partly insection. Fig. 2 is a top or plan view partly in section. Figs. 3, 4, and 5 are sections taken on the lines zr, y y, and .e z, respectively, Fig. l.V Fig. 6 is a vertical longitudinal section taken through the keeper located on the threaded reciproeatin g shaft, the parts being shown on a larger scale. This section may beconsidered taken on the line fu o, Fig. 7. Fig. 7 is a section taken on the line pp, Fig. 6.

Similar reference characters indicating corresponding parts in the views, let the numeral 5 designate a casing composed of two parts fastened together in any suitable manner, as by passing bolts through apertured lugs 5a, formed integral with the casing parts. This casin g is adapted to be adj ustably secured to any suitable stationary support. For this purpose the casing is provided with an apertured projection 5C. Within this casing 5 is located a shaft 6, whose central portion is provided with a screw-thread. The extremity 6a of this shaft forms a chuck or socket for the reception of the drill-bit. Located on the threaded portion of the shaft is the keeper 7, composed of the collar 7a, slotted to receive the dogs 7 C, which are pivoted on pins 7d and notched to engage the screw-threads of the shaft. To one endof the collar are attached the leaf-springs 7h, which engage the dogs and maintain them normally in engagement with the shaft, whereby the keeper is locked thereon. The pivot'pins pass through the rear eX- tremities of the dogs or the ends farthest to the left, referring to Figs. 1 and 2. The opposite extremities of the dogs are curved outwardl y, as shown at 7 j to engage beveled stops 8, formed in the casing and adapted to throw the dogs outwardly sufficiently to disengage their teeth from the screw-threads of the shaft, whereby the latter is released from the keeper. The stops 8 are so located that the dogs engage the stops and release the shaft just before the latter reaches its forward limit of movement, or just before the drillbit engagesthe rock. Hence the shaft being released from the keeper at the proper moment feeds itself into the rock during every forward stroke of its reeiprocaticn.

The teethof the dogs 7'g diminish in depth from the parts 7J' rearwardly or toward. the pivot-pins 7, in order that all the teeth of each dog may disengage or leave the screwthread of the shaft simultaneously. The collar 7 of the keeper is, provided with projections 7, located on diametrically opposite sides thereof and formed integral therewith 0r attached thereto. Surrounding the shaft 6, to the rear of the keeper, is a coil-spring 9. The forward extremity of this spring engages the keeper, while the rear extremity thereof bear's against a stop formed on the casing. Located on the shaft forward of the keeper is a collar lO, havinginclined ridges, projections, 0r teeth arranged thereon at regular intervals, whereby they are equidistant from one another. v p

The shaft is provided with a groove 6c, which engages a counterpart spline or feather Aformed on the collar 10, whereby the shaft is permitted to move longitudinally in the col- ,j

lar. The casing is provided with a circumferential groove which locks the collar against longitudinal movement on the casing, but permits it to rotate with the shaft.

a transverse shaft 12, carrying S-shaped cams i 13, one of which is adapted to engage the in clined projections on collar 10, while both of said cams engage the projections 7m`of the keeper as the cam-shaft is rotated. It will be observed that the projections on the collar 10 ICO protrude through an opening in the casing,

while the casing is slotted to allow the projec-l tions 7n to protrude therethrough and slide longitudinally therein. To one extremity of the cam-shaft is attached a hand-crank 14, through whose instrumentality the shaft may be rotated.

From the foregoing description the operation of the device will be readily understood. As the cam-shaft is rotated, the S-shaped cams first engage the projections 7m of the keeper and carry the shaft 6 and the keeper backward compressing the coil-spring. rlhe cams 13 are so shaped that while the shaft is making the backward movement one of the cams engages a projection on the collar 10 and gives the drill-bit a partial rotation. As soon as the keeper is released 'from engagement with the cams, the shaft 6 is forcibly driven forward by the recoil of the spring 9, and just before the drill reaches the rock the dogs of the keeper engage the beveled stops on the casing and dis'engage the keeper from the drill-shaft, the momentum of which drives the drill forward into the rock at each successive forward stroke. After each forward stroke of the drill-shaft and as the earns again engage the projections 7 of the keeper and begin to force thelatter backward from the stops 8 of the easing, the springs 7h force the dogs to engagement with the shaft 6, which is again carried backward, given a partial rotation, and released, as already described.

Having thus described my invention, what I claim is- 1. In a rock drill, the combination with the casing, of a longitudinally movable screwthreaded shaft 6 mounted on the casing and carrying a drill bit, a rotatable shaft 12 journaled in the casing and carrying cams, a keeper comprising a collar surrounding the shaft 6, and spring-actuated dogs or grippers pivoted on the collar and threaded to engage the screw threads of the shaft whereby the keeper and shaft are normally locked together, the collar of the keeper having lateral projections lying in the path of the cam on shaft 12, stops located on the casing and adapted to engage the dogs and unlock the keeper while the shaft is making the forward movement, substantially as described.

2. In a rock drill, the combination with the casing, of the longitudinally movable shaft 6 supported on the casing, a rotatable shaft 12 journaled in the casing and carrying an S- shaped cam, the keeper normally locked on the shaft and carrying a projection lying in the path of the cam, a collar surrounding the shaft and locked from longitudinal movement on the casing, the shaft and collar being connected by a spline on one part engaging a groove in the other part, the collar being provided with exterior projections all lying successively in the path of the cam, the casing being shaped to engage and unlock the keeper during the forward movement ofthe shaft 6, substantially as described.

3. In a rock drill, the combination with the casing, of a longitudinally movable screw threaded shaft 6 supported on the casing, the notched spring-actuated grippers engaging said shaft, a rotatable shaft 12 journaled in the casing and carrying a cam, a collar surrounding the shaft G and locked from longitudinal movement on the casing, the shaft G and the collar being connected by a spline on one part engaging a groove on the other part, the collar being provided with exterior projections all lying successively in the path of the cam, whereby as the shaft 12 is rotated,

the partial rotation between strokes is imparted to the drill shaft (5, substantially as described.

In testimony whereof I affix my signature in the presence of two witnesses.

TIIERON W. CHAPMAN.

Witnesses:

G. J. ROLLANDET, ALFRED J. OBRIEN. 

